<item ident="F4-6141" title="F4 | Implicit solutions for exact IVPs | ver. 6141"> <itemmetadata> <qtimetadata> <qtimetadatafield> <fieldlabel>question_type</fieldlabel> <fieldentry>essay_question</fieldentry> </qtimetadatafield> </qtimetadata> </itemmetadata> <presentation> <material> <mattextxml> <div class="exercise-statement"> <p> <strong>F4.</strong> </p> <p> Determine which of the following ODEs is exact. </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" alt="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" title="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" data-latex="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}"/> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y" alt="12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y" title="12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y" data-latex="12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y"/> </p> <p> Then find an implicit solution for this exact ODE satisfying the initial value <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y( -1 )= 1" alt="y( -1 )= 1" title="y( -1 )= 1" data-latex="y( -1 )= 1"/>. </p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-statement"> <p> <strong>F4.</strong> </p> <p> Determine which of the following ODEs is exact. </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?3%20%5C,%20t%5E%7B2%7D%20%7By'%7D%20+%206%20%5C,%20t%20y%20+%202%20%5C,%20t%20%7By'%7D%20+%202%20%5C,%20y%20=%204%20%5C,%20y%5E%7B3%7D%20%7By'%7D" alt="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" title="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" data-latex="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}"> </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?12%20%5C,%20t%5E%7B3%7D%20-%202%20%5C,%20y%20=%20-8%20%5C,%20t%5E%7B2%7D%20y%20%7By'%7D%20-%204%20%5C,%20y%5E%7B3%7D%20%7By'%7D%20+%208%20%5C,%20t%20y%20%7By'%7D%20+%206%20%5C,%20t%20y" alt="12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y" title="12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y" data-latex="12 \, t^{3} - 2 \, y = -8 \, t^{2} y {y'} - 4 \, y^{3} {y'} + 8 \, t y {y'} + 6 \, t y"> </p> <p> Then find an implicit solution for this exact ODE satisfying the initial value <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?y(%20-1%20)=%201" alt="y( -1 )= 1" title="y( -1 )= 1" data-latex="y( -1 )= 1">. </p> </div> </mattext> </material> <response_str ident="response1" rcardinality="Single"> <render_fib> <response_label ident="answer1" rshuffle="No"/> </render_fib> </response_str> </presentation> <itemfeedback ident="general_fb"> <flow_mat> <material> <mattextxml> <div class="exercise-answer"> <h4>Partial Answer:</h4> <p>The following ODE is exact.</p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" alt="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" title="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" data-latex="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}"/> </p> <p> Its implicit solution satisfying the initial value is: </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-y^{4} + 3 \, t^{2} y + 2 \, t y = 0" alt="-y^{4} + 3 \, t^{2} y + 2 \, t y = 0" title="-y^{4} + 3 \, t^{2} y + 2 \, t y = 0" data-latex="-y^{4} + 3 \, t^{2} y + 2 \, t y = 0"/> </p> </div> </mattextxml> <mattext texttype="text/html"><div class="exercise-answer"> <h4>Partial Answer:</h4> <p>The following ODE is exact.</p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?3%20%5C,%20t%5E%7B2%7D%20%7By'%7D%20+%206%20%5C,%20t%20y%20+%202%20%5C,%20t%20%7By'%7D%20+%202%20%5C,%20y%20=%204%20%5C,%20y%5E%7B3%7D%20%7By'%7D" alt="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" title="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}" data-latex="3 \, t^{2} {y'} + 6 \, t y + 2 \, t {y'} + 2 \, y = 4 \, y^{3} {y'}"> </p> <p> Its implicit solution satisfying the initial value is: </p> <p style="text-align:center;"> <img style="border:1px #ddd solid;padding:5px;border-radius:5px;" src="https://latex.codecogs.com/svg.latex?-y%5E%7B4%7D%20+%203%20%5C,%20t%5E%7B2%7D%20y%20+%202%20%5C,%20t%20y%20=%200" alt="-y^{4} + 3 \, t^{2} y + 2 \, t y = 0" title="-y^{4} + 3 \, t^{2} y + 2 \, t y = 0" data-latex="-y^{4} + 3 \, t^{2} y + 2 \, t y = 0"> </p> </div> </mattext> </material> </flow_mat> </itemfeedback> </item>